Think pink: Number of women with breast cancer may double in next 15 years, study finds

A doctor exams mammograms, a special type of X-ray of the breasts, which is used to detect tumours as part of a regular cancer prevention medical check-up (Reuters/Eric Gaillard) / Reuters

By 2030, the number of women expected to develop breast cancer will increase by about 50 percent, according to a new study. Currently, one in eight women will develop the disease at some point in her lifetime.

The study combined two types of breast cancers ‒ invasive and
in-situ ‒ to make its projections, according to study author
Philip S. Rosenberg, PhD, a senior investigator in cancer
epidemiology and genetics at the National Cancer Institute (NCI).

Breast cancers are the most common type of malignant tumors in
the US, with 283,000 diagnosed cases in 2011. That number is
expected to rise to about 441,000 in 2030, researchers found.

The numbers the team put forward in its study aren’t as scary as
they seem, though, because the increase is driven by three
factors, Rosenberg said.

Firstly, people are living longer, so women who don’t die of
other causes are more likely to develop breast cancer. Secondly,
there are more female Baby Boomers than there were women of the
Greatest Generation, and those Boomers will reach an age where
they are more likely to get breast cancer over the next 15 years.
Finally there is a rising rate of estrogen receptor (ER) positive
cancer, which the study projects forward.

Rosenberg and his colleagues sought to estimate the future
incidence of new cases of breast cancer, as well as the burden
those cases will put on the health care system. They believe
their estimates will help the oncology community to “develop
a proactive roadmap to optimize prevention and treatment
strategies,” they said in a statement.

"Although breast cancer overall is going to increase,
different subtypes of breast cancer are moving in different
directions and on different trajectories," Rosenberg said in
the statement, referring to whether tumors are invasive, in-situ
or ER-positive or ER-negative.

“These distinct patterns within the overall breast cancer
picture highlight key research opportunities that could inform
smarter screening and kinder, gentler, and more effective
treatment,” he continued.

The NCI group found that the number of ER-negative breast cancers
is expected to drop in coming years, and those tumors can be
among the most difficult to treat, Rosenberg told HealthDay.

"There could be a breast cancer-prevention clue in that
decline," Rosenberg said. "Understanding the 'why'
behind the trend will be very important."

Another factor that increased the projected breast cancer rate is
the NCI study’s inclusion of carcinomas in-situ (CIS) ‒ or
smaller tumors that have not spread to neighboring tissues. There
is a debate as to whether CIS should be considered a cancer at
all, and whether early screening through mammograms and monthly
breast self-exams leads to over treating tumors that may not have
grown or become malignant.

“There’s certainly concern, especially in the older patients,
about over-diagnosis of breast cancer, and that’s one of the
reasons that screening mammography can become very controversial
in older patients,” Dr. Sharon Giordano, MPH, department
chair of health services research at MD Anderson Cancer Center,
told Time. “We don’t want to end up diagnosing and treating a
disease that would never cause a problem during the person’s
natural lifetime.”

Not all in-situ breast cancer progresses into a dangerous
condition, said Giordano, who was not involved in the research.

“One of the unanswered questions is, how do we identify the
in-situ cancers that are the ones that go on and progress to a
life-threatening illness, and which are the ones that we should
be leaving alone and not subjecting people to invasive surgery
and radiation for treatment?” she asked.

Last July, a panel from the National Cancer Institute concluded
that improved screening has resulted in the over-diagnosis and
over-treatment of cancers that are not life-threatening, without
significantly reducing the death rate from the disease, the
Washington Post reported.

Rosenberg will present the study’s finding at the American
Association for Cancer Research’s annual meeting this week. His
team used cancer surveillance data, census data and mathematical
models to arrive at their projections.